Tom Oden, writing in his book Requiem[1] way back in 1995, explains how it happens.

The first step is always a study committee.

In response to claims for moral legitimization of behaviors widely thought displeasing to God, each of the mainline denominations has dutifully appointed elaborate study commissions to report back to the general legislative body on how the church might respond to this form of sexual orientation, practice, and advocacy. (152)

If the first study committee comes back with a traditional reading of the text, or if the legislative body dismisses the committee’s progressive interpretation, you can always assign another study committee amidst outcries that the recalcitrant conservatives suffer from “homophobia and reactionary stupidity” (153).

And if the traditional view cannot be overturned right away, try dismissing the whole controversy by telling people (with no small amount of chronological snobbery) that saner Christians understand this is nothing worth fighting over.

The fact that homosexual practice is not a weighty moral matter was asserted by the United Methodist Sexuality Report as a “consensus among Christian ethicists,” yet without any evidence to support this curious assertion. All the conspicuous Christian teachers who have resisted same-sex intercourse (John Chrysostom, Augustine, Thomas Aquinas, Martin Luther, John Calvin, and other consensual ecumenical teachers) are weighed in the debate less heavily than selected modern proponents of moral relativism and utilitarian permissivism. (153)

The next step is admonish “the people of God to wait for a firm ‘scientific consensus'” on the matter (154).

Then some leading lights in the denomination can offer new exegetical avenues for avoiding the traditional understanding of familiar texts. Three evasions in particular are quite popular.

The first evasion is that the normative moral force of all biblical texts on same-sex intercourse may be explained away by their cultural context. This leads to the conclusion that any statement in the Bible can be reduced to culturally equivocal ambiguity and indeterminacy on the premise of cultural relativism…

The second evasion hinges upon a strung out interpretation on Romans 1:26-27…

The third evasion argues that when Genesis 1:27 declares that God created male and female, the text has no normative significance for how sexual behavior is to be understood, since it is merely a distinction with no further moral meaning. (154-55)

If all else fails, the final step is to announce triumphantly and with a terrific celebration of grace that “Christ is, in an amoral fashion, the end of the law” and charge others with legalism if they don’t share in your antinomianism (156).